Handling CAST Error On The Fly

I want to load a smallint field with values from a varchar field; e.g. CAST(field as SMALLINT). This is in a bulk copy insert so of course there are the few fields that have '1773A' for example and error out the CAST. Anyone know of a way to return 0 (or 1) if CAST errors on conversion ?

This is the test script that's trying to convert 3750 records (an unknown minority of records contain alpha characters):

create table alstest (field1 smallint)
insert into alstest (field1)
select CAST(conf_number AS SMALLINT) from conference